Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 221144 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
544 AM CST Thu Feb 22 2018

.DISCUSSION...Updated for latest aviation discussion below.

&&

.AVIATION...Cold front has moved offshore and is expected to pull
up stationary just south of the River this morning before
returning north as a warm front tonight. Morning sounding shows a
very shallow cool air mass over the region with south winds at
about 500 feet above the surface. This will maintain LIFR cigs
this morning with some IFR vsby as fog and drizzle develop. The
cool air deepens ever so slightly this afternoon with cigs
possibly nearing MVFR for a few hours late afternoon and evening
before cigs and vsby lower back to IFR tonight as the front
returns north. Isolated showers this morning to move rapidly north
producing brief moderate rain. Light north winds may gusts to
around 15 knots later this morning and afternoon.


.PREV DISCUSSION... /issued 409 AM CST Thu Feb 22 2018/

SHORT TERM (Now through Friday): The front has continued to
slide southward through the night, and has cleared all land areas.
North winds behind the front have brought much cooler
temperatures, currently in the upper 40s for the ranchlands and in
the 50s along the river. Cold advection will hold temperatures
steady in the 50s and lower 60s through most of the day. Most
precipitation will remain along the front, so overall chances
today remain fairly low, with maybe some brief dz possible. Once
the progression of the front has stopped, southeasterly flow will
begin to push it right back to the north late this afternoon. As
the front passes back through, it will interact with another
midlevel impulse riding around the bottom of the broad upper
trough along the Rockies. This will spark an increased chance for
showers, especially across the ranchlands closer to the front.
Temperatures overnight will remain steady or slowly rise as the
southeast flow pushes the cold air back out. Substantial warm air
advection will push temperatures well into the upper 70s and lower
80s tomorrow afternoon.

LONG TERM (Friday Night through Wednesday):An active split flow
will be featured across the Lower 48 and Mexico with a series of
shortwave troughs moving through the broad mid/upper level trough
over the West and into the Central plains. Models are trending
initially strong with these shortwaves as they move into the
California and the Desert SW than weaken them as they move into
the Plains. Despite the weakening of the troughs this will lead to
formation of low pressure areas over the Front Range of the
Rockies and Plains keeping an active late Winter early Spring
pattern alive this weekend and next week.

The initial shortwave and surface low develops Friday night and
Saturday with a strengthening low level jet resulting in strong
winds Saturday. Models continue to show the strongest winds over
the eastern coastal counties where winds advisory conditions are
likely to occur Saturday afternoon. A low pressure trough
develops ahead of a cold front with a downsloping wind component
to exaggerate the warming affect pushing temperatures into the
80s to the lower 90s. The next Cold front begins to work its way
into the CWA Sunday with a strengthening upper jet over Central
Texas. This should be enough to move through the front into our
region but likely to slow down with a weak push off the coast
Sunday night or Monday. Temperatures to cool off slightly as
clouds and rain showers increase around the frontal boundary. Next
Upstream trough takes shape Tuesday and Wednesday with Monday`s
front returning as a warm front Tuesday and Southerly winds
strengthening for Wednesday with another potential for a frontal
passage Thursday.

GFS/EC model temp/pop guidance are in good agreement with the warm
up on Saturday, the chance of rain and brief cool down
Sunday/Monday then the warming back above seasonal averages for
the end of this long term package.

MARINE:(Now through Friday): The front has pushed into the Gulf
waters in the past couple hours, and is slowly to a halt just
offshore. Areas north and west of the front will see modest
northerly winds, while areas south of the front will continue with
southerly flow. This opposing flow will continue to churn up local
waters, with seas reaching 5 to 6 feet. The front has passed the
laguna completely, and will see continued northerly winds today
around 10 knots, causing choppy waters through this afternoon. The
front pushes right back to the north overnight tonight, with modest
southeast flow returning to all waters by midnight tonight. Wave
agitation will slowly relax late tomorrow, with seas hovering around
5 feet.

Friday night through Monday...Stronger southeast winds develop
Friday night and Saturday as deep low pressure area develops over
the Southern/Central Plains. Small Craft advisory conditions are
likely to develop Saturday before a weak cold front works slowly
through the coastal waters Sunday into Monday. Light to moderate
northeast winds expected behind Sunday/Monday`s front along with a
moderate sea.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&

$$

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